Build your own mobile computer with the Raspberry Pi for $120

I recommend the RasPi B+ model because of the additional USB ports. Four total USB ports provide enough USB slots to add WiFI, a bluetooth keyboard, an external hard drive and a USB monitor. As I built mine I found a few additional options that work well with the RasPi B+ model that you may find useful for your project.

Lessons Learned:
Like any project there were a few lessons learned along the way. I hope these lessons save you some time.

The Raspberry Pi B+ has 4 USB ports instead of 2 like the A and B, which is what I needed to connect all the peripherals.

The Raspberry Pi B+ uses a MicroSD card not an SD card. A USB MicroSD Card Reader is useful to transfer the Pidora operating system from your computer to the MicroSD card.

Most USB hubs will backfeed power to the Pi. There’s no voltage regulator on the USB ports of the Pi so you need to either purchase a USB hub that doesn’t backfeed power, use the power cord instead of the USB power, or take your chances with a power surge from the hub. Note: The safety instructions with your Pi recommend against powering the Pi via USB.

The USB port on the monitor is in a bad place. It’s located under the rotating leg.

The monitor being purchased can be fed video via USB. When you travel you can use the HDMI port and use a TV at the hotel or the VGA jack to some other monitor.

The monitor can be powered and have video fed from a USB port. Is there enough power from the Pi?

You can buy a power cable at 1.5V, but if you plan to use all four USB ports you probably want a 2.5V power cable. The one I’m purchasing is 2000mA.

Item List

Item

Price

Ordered

Delivered

Raspberry Pi B+ 512MB

$38.45

29 Oct

12 Nov

Case for the B+

$10.99

29 Oct

12 Nov

2.5V 2000mA Power Supply for the B+

$6.39

29 Oct

5 Nov

32GB MicroSD card

$17.99

29 Oct

12 Nov

WiFi USB Dongle

$7.49

29 Oct

12 Nov

Logitech keyboard/mouse

$28.49

29 Oct

12 Nov

HDMI to VGA female cable (optional)

$4.13

29 Oct

USB MicroSD reader/writer (optional)

$5.95

29 Oct

12 Nov

TOTAL

$119.88

Once everything is up and running I plan on purchasing the AOC 16″ USB powered monitor ($86.99). I purchased an HDMI to VGA cable to be able to use an analog monitor that I already have at home before purchasing the USB monitor.

I looked at all of my electronics at home and my laptop has a slot for an SD card, but not a MicroSD. The only device I have that has a MicroSD card slot is an old flip cell phone. Instead of trying to figure out how to get the operating system written to the MicroSD on the phone I went the easy route and bought a USB MicroSD reader/writer so I can do it straight from my laptop. A lot of reviews say these are cheaply built so I splurged on the $6 one instead of the $1.50 one. Note: The MicroSD card ships with an SD adaptor so it will work in my laptop after all.

Items Received
It took 2 weeks, but I received everything except the HDMI to VGA cable, which I need in order to use a spare computer monitor as the screen. That’s not due for another 2 weeks so in the meantime I’ve connected the RasPi to my TV using an HDMI cable.

One thing I noticed is neither the case nor the RasPi come with mini screws to secure the RasPi to the case. The case snaps tightly closed though. Also, the safety pamphlet says to use a 5v DC power source with a minimum 600-1800mA. Hopefully the 1800mA is a minimum not a maximum so my 2000mA power supply will work.

You’ll want to load the OS onto your MicroSD card and insert it into the Raspberry Pi before you put the Pi in the case. The MicroSD card slot is on the underside of the RasPi.

-Getting the peripherals powered and working
Note: Nothing to worry about here. The bluetooth laptop worked out of the box without having to configure anything. The wireless was simple to configure using two commands. View how to configure your Raspberry Pi wireless settings here.